andees



(No Model.) 5 sheetssheet 1.

G. L. ANDERS. TELEPHONE SYSTEM.

N0..5oo,545. -f Patented Ju1y4, 1893.

(No Model.) 5 Sheets-Sheet 2.

G. L. ANDERS. TELEPHONE SYSTEM.

No. 500,545; Patented July 4, 1893.

G. L. ANDERS. TELEPHONE SYSTEM'.

5 Sheets-Sheet 3.

(No Model.)

No. 500,545. Patented July 4, 1893.

m WM MSN (ING Model) 5 Sheets-Sheet 4. G. L. ANDERS.

TELEPHONE'SYSTEM. No. 500,545. Patented July 4, 1893.

(No Model.) 5 sheets-*sheen 5.

G. LIANDERS.- TELEPHONE SYSTEM.

No. 500,545. Patented July 4, 1893.

UNTTED STATES PATENT OFFICE.

GEORGE LEE ANDERS, OF LONDON, ENGLAND, ASSIGNOR OF THREE-FOURTHS TOWALTHER KTTGEN, OF SAME PLACE.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 500,545, dated July 4,1893.

Application filed December 1I 1892. Serial No. 453.763. (No model.)

To all whom it may concer-nl: the mouthpiece diaphragm, holding ring orBe it known that I, GEORGE LEE ANDERS, magnets. Fig. 11is adiagramshowing the cira subject of the Qiieenof Great Britain, recuits throughthree instruments constructed siding at Sydenham, London,in the countyof in accordance with the above. Fig. 12 is a 55 Kent,England,haveinvented certain newand sectional elevation of a modified form oftransuseful Improvements in and Connected wit-h mitter with the receiverin place. Fig. 13 is Telephones, of which the following is a specia backview of the modified transmitter. Fig. fication. 14 is a front view withthe receiver removed.

My invention relates toirnproved telephonie Fig. is a front View withthe receiver and 6o 1o apparatus consisting of a combined telephonecover plate removed and Fig. 16 is a diagram transmitter, receiver,ringing key and switchillustrating the circuits between two instruboard,suoli an apparatus being adapted more ments of this type. particularlyfor domestic use such as in hotels The base 1 of the apparatus which isof or large buildings where it is desirable that vulcanite forms thepart which I term the 65 i5 an individual in an office or bureau may beswitchboard. To this base is attached by able to communicate with anumber of rooms suitable screws (not shown) the main body 2 ordepartments, the switchboard which is comof the apparatus which is ofinsulating matebined with the apparatus being provided for rial. Theswitchboard has a number of brass this purpose. Such switchboard isoperated plates 3 arranged in a circle and sunk therein. 7o zo by meansof a plug which is placed by the As shown there are fourteen of theseplates 3 person wishing to make communication in one having holestherein for the reception of a of a number of holes arranged around theinplug and one plate 4 which carries a projectstrument. The apparatusishowever adapted ing stud 5. One of the plates 3n carries a stud forother more extended or public uses when 45. The arrangement shownenables the user 75 in connection with other apparatus of the of theinstrument to communicate with foursame construction vas will be evidentfrom its teen different persons or departments as each construction andoperation which are hereinof the plates 3 is in electrical connectionwith after described. a wire passing to the instrument of such per- Myinvention also relates toa modified form sons or departments. The backof the body 8o 3o of instrument without the switchboard as 2 Fig. 2 hasa brass ring 9sunk into thewood hereinafter described. ush with thesurface 10 on which latter are ln the accompanying drawings Figure 1 issix brass blocks A. B. C. D. E. F. The ring a vertical section throughthe combined ap- 9 has fourteen holes therein which correspond paratus.Fig. 2 is a view of `the back on the to those in the plates 3 andcarries also p ro- S5 line x--m Fig. 1 looking to the left the base orjecting studs 11 and 12. On the surface lOis switchboard being removed.Fig. 3 is a view pivoted a block 13 of insulating material such of theswitchboard on the line x- Fig. 1 block having a slot with which thestud 1l looking to the right. Fig. 4. is a vertical secengages andcarrying a metal strip 14 such tion through the switchboard. Fig. 5 is astrip having a portion turned down beneath 9o 4o front view of theapparatus with the receiver the block 13 as shown in Fig. l so as tomake and ringing-key removed. Fig. 6 is also a electrical contact withthe pivot screw 15. front view, but showing the-front plate and The stud12 has a constant pressure placed transmitter diaphragm removed inaddition upon it by means of a spring 16 attached to to the receiver andringing key. Fig. 7 is a the blockA which acts to cause the ring 9 to 95side elevation of the transmitter and switch` be held inthe groove ofthebody 2 in which board portion of the apparatus. Fig. 8 is a it is sunk,in such a position that the pin 11 side elevation of the receiverremoved from keeps the pivoted block 13 pressed over so the transmitter.Fig. 9 is a front view of t-he that the right hand side of the strip 14(lookreceiver with the mouthpiece diaphragm and ing at Fig. 2) isnormally in contact with the Ico 5o holding ring removed. Fig. 10 is aside secblock F. By this means the ring 9 it will be tional elevation ofthe receiver case without seen is held so that the holes in same are outof line with a similar number of holes 17 in the body 2. When however aplug such as G is inserted in the holes in theinstrument the effect willbe to cause the holes in the ring 9 to be brought into line with theholes 17 so that such ring will be shifted, the block 13 will be rockedand one end of the strip 14 will be removed from contact with the blockF and the other end will be brought into contact with the block E, thespring 16 returning the ring when the plug is withdrawn. The strip 14 isalways in contact with the block D by means of a wire 54 shown in Fig.2.

The ring 9 has riveted to it and in electrical contact therewith aforked strip 18 the long arm or piece 19 of which is bent over as shownin Figs. 1 and 2 and forms one of the contact pieces of the ringing keysuch piece 19 being acted on by the head 2O of the push button 21, whichwhen operated will force the piece 19 into contact with the stud 5 andcomplete the battery circuit for ringing a distant bell. The piece 19 isof course moved with the ring but is sufficiently wide not to entirelypass the pressing head 2O when the ring is moved.

The ring 9 is cut away beneath the piece 19 to permit of a stud- 22passing through same without beingin contact therewith such stud 22being in contact with the under side of the strip 19 except where thelatter' is eperatcd by the push button 21. The otherend of the stud 22is attached to the base of a spring switch strip 23 Figs. 1 and 6 on thefront of the body7 portion 2. Through ther body 2 is a central hole inwhich is held the transmitter microphone. This consists of two hardcarbon blocks 24, 24 which are cup shaped in their interior facesbetween which is placed a mass of carbonized fiber 25. This ispreferably a cotton ber which before or after carbouization may beimpregnated with fine carbon or plumbago. To retain this be tween thecup shaped faces of the carbon blocks a short piece of rubber tubing 26is placedover the two blocks. The rear block 24 is held in the centralhole of the body by means ofaplate 27 one arm of which is screwed to theblock C and is in electrical contact therewith while the other snort armis attached to the body 2 by a screw 28. The rear block 24 is attachedto the plate 27 by a screw 29 while the front block is attached byascrew 30 to the diaphragm 31 awire or strip 47 passing from the screw 30tothe base of a retaining piece 33. Other forms of microphones mayhowever be employed, but I have found the carbonized fiber employedloosely in this wayto be of great advantage as it is capable of beingused in any position. It may be used however in various ways, but thatillustrated will work well.

The blocks A. B. E. F. slightly overlap the ring 9 `for the purpose ofkeeping it in its `place the blocks B E F havinga thin piece ofinsulating material beneath them as shown in the case of the block EFig. 1. The blocks C D do not overlap the ring-and the blocks B C D E Fhave screw terminals B CD E F on them. The front of the body 2 isrecessed as shown in Figs. 1 and 6 and on the lowest surface 46 itcarries a curved metal strip 32. One end of this strip 32 is secured bya screw 32 to the body 2 such screw making electric contact with theblock B on the other side. The free end of the strip 32 is bent up toform one piece of a contact maker or switch such end projecting throughan opening in the diaphragm as shown in Fig. 1. The other piece of theswitch is the switch strip 23 before referred to. This strip 23 is bentas shown in Fig. 1 and passes across the face of the diaphragm its freeend being in contact with the retaining piece 33 before referred to whenthe receiver is removed. The switch strip 23 carries on its uppersurface a metal strip 34 bent up to form a nose which projectsthrough a slot in a perforated cover plate 35. This cover plate servesto protect the diaphragm. It is secured by small screws to or may formpart of the metal cover 36. This cover has a projecting yoke 37a portionof the way around same such yoke being undercut or beveled as shown inFig. 1 to hold the receiver, the vulcanite mouthpiece 38 of which has acorrespondingly beveled fiange to engage therewith. In this position itwill press on the nose of the strip 34 as shown in Fig. 1, by thewedging action of the flange in the yoke and so cause the strip 23 tobreak contact with the retaining piece 33 and make contact with thecurved strip 32. Around the iiange of the cover 36 are fourteen holescorresponding to the holes 17 in the body 2.

The receiver comprises an ordinary bent magnet 39 the two ends of whichare turned up to receive the bobbins 40. The magnets are secured to theback of the receiver which is of vulcanite its exterior face being arosette or other ornamental shape. Two wires only are employed forconnecting the receiver with the transmitter and these are marked fu; w,are conducted through the case of the receiver and are connected to thecoils as shown in Fig. 9 their other ends being connected to the blocksC and D respectively as shown in Fig. 2.

For the purpose of keeping the diaphragm 41 of the receiver at thecorrect distance from the magnets 1 have devised the arrangement shown.This consists of a ring 42 which may be open as shown which is slippedinto the case 43 and abuts against the backof the receiver, in whichposition it is Hush with or projects slightly beyond the outer edge ofthe case. This ring is of a depth corresponding to the distance that thediaphragm is to be from the back of the receiver, the mouthpiece isplaced on this and the parts are secured together bya clamping ring 44one edge of which is turned over to hold the mouth piece while the otherend is threaded to en- IOO gage with a thread on the case 43. Thearrangement described obviates the use of packing rings and liketroublesome devices for obtaining and preserving the correct distancebetween the diaphragm and the magnets and is also a very convenientmethod of holding the parts together. A part of the object of the plug21 has been previously explained that is for thepurpose of shifting thering 9 and strip 14. Its further purpose when it is placed in one of theholes on the face of the instrument (which holes are lettered, numberedor otherwise marked to indicate dierent persons or departments) is tomake contact between the ring 9 and one of the fourteen plates on thebase 1 which plates as before stated are in connection with theparticular line wire desired. The eect of the entrance of the plug is toshift the ring and this4 shifting causes the stud 12 to be moved out ofcontact with the stud 45 with which it is normally in contact asindicated in Fig. 3 such contact being broken until the plug iswithdrawn.

In the operation of the instrument the receiver is first removed, theplug is placed in the desired hole and the ringing key 21 is operated.The mouthpiece of the transmitter is now exposed for use and thereceiver being placed to the ear communication with the desired stationis established. The circuits through the instrument are as followsreference being made to the diagram Fig. l1: Supposing a current iscoming into the instrument the receiver being in the transmittermouthpiece as indicated at No. 3 station no plug being in theinstrument, the path of the current is from the line wire III to theplate 3a on the switchboard from latter to stud 45 (not shown here)which is in contact with stud 12, stud 12 to ring 9 from latter to key19 to stud 22 through stud22 to strip 23 from latter through strip 32 toblockBout through signal bell to block F and to earth or return wire 49.To send a signal the receiver is taken out as shown at No. 1 station,the plug G is placed in the particular hole belonging to the person tobe called up and the current is from batterywire 50 to blockE fromlatter to plate 4 on switchboard from plate 4 to key 19 when depressedthrough strip 18 to ring 9 and from latter through the` plug to theparticular blockconnected to the wire desired as represented at No. 1station where the plug G is illustrated as being in one of the holes andin connection with line wire lI from whence it will go to station No. 2.enters by wire II and the receiver being in the instrument the circuitsare as described previously in the/case of No. 3 station. As shownhowever the receiver in No. 2 station is out as Nos. 1 and 2 aresupposed to be talking as will be hereinafter described.

The foregoing illustrates the path of the current from block E to plate4when the key 19 is put into contact therewith so that the whole forceofthe battery is caused to pass yearth 49.

through the wires but it will be seen that there is 'also a circuit fromplate E through strip 14 wire 54 terminal D through receiver to terminalC by plate 27 through the microphone out by strip 47 to contact piece 33switch 23 stud 22 key 19 strip 18 ring 9 through plug to the plate onthe switchboard and from that to wire II. The current by this pathhowever passing through the receiver and transmitter may not besufficient to ring the distant bell and it is herefore desirable topress the key. The bell having been rung at No. 2 station the circuitwhich is now required to be through trans mitters and receivers is asfollowsz--The plug G being in one of the holes as shown' at No. 1station and the receiver being out the current is from battery wire 50to block E through strip 14 as heretofore described to wire II. by linewire through wire II to No. 2 to plate 3DM by studs 45 and 12 to ring 9by strip 18 and key 19 to stud 22 switch 23 contact 33 strip or wire 47through microphone disk 27 block C wire w through receiver to block Dwire 54 to strip 14 and by block F through wire 52 to return or Thediagram will be easily understood from the foregoing description itbeing understood thatthe fourth wire shown which is not numbered passesto the fourth station and that a fifth wire is used for the fifthstation and so on for the fourteen stations. It will be seen that bythis system of intercommunication a wire which is normally a return`wire and a battery wire of one polarity only is used which may berepresented by the symbol N-i-2 instead of as is usual N-l-3. N beingthe number of stations and 3 being one return and two battery wires ofopposite polarity. According to my arrangement the rocking block 13 actsto disconnect the apparatus desiring to call a station from that pole ofthe battery to which it is normally connected and to connect it to theopposite pole so that the use of the third wire is dispensed with. Itwill be further seen that by this system there is no chance ofoverhearing a conversation going on between other parties as the simpleremoval of the receiver from the transmitter will not establish abattery circuit through the instrument of the person attempting tolisten. A i.

Where the instrument such as I have heretofore described is to be usedonly for the intercommunication of two persons or stations I modify thesame as shown in Figs. 12 to 16.

The instrument for the above purpose is necessarily much simplified butcontains the main features of my invention. The receiver it will be seenis of the same construction as that previously described.

The face plate 35 of the transmitter may be perforated as previouslydescribed or have a central opening only as shown. The microphone may bethe same as shown in Fig. 1 but I have here shown only one cup shapedblock 24 in the recess of which is contained the carbonized iiber 25 theblock 24 attached IIO to the diaphragm 3l being a iiat disk. Such blockis in communication by means of awire or strip 47 with a s crew47 Figs.14 and 15 which passes through the body 2 to the terminal C Fig. 13. Therear block 24 is connected by a wire or strip 47b to the terminal E astud 5 on which forms one contact point of the ringing key 19. This key19 is in contact with the switch strip-23 as shown in Fig. 12 exceptwhen pressed in. The other end of the key 19 is in contact with theterminal A by means of a screw 19. The strip 32 is attached to ,the bodyby a screw 32a which makes contact with the terminal D. The other end ofthe strip is in connection with a screw 32b forniing the other contactpoint of the switch strip 23 when the latter is pressed in by thereceiver. When the receiver is out the nose 34 makes contact with theunder side of the yoke 37. The terminal B is in contact with the metalflange 36 by means of a-screw 36 said screw projecting through the body2 so that its point is in contact with and enters the flange the latterbeing prevented from coming into contact with any other part by means ofan insulating packing ring 36b beneath same. The circuit through theinstrument is as follows reference being made partly to the diagram Fig.16 which shows both receivers as removed from the transmitter and readyfor conversation and partly to the preceding Iigures: The current fromthe battery passes by way of a wire to terminal E from thence by wire47b through microphone by wire 47 to terminal C from the latter throughWires w w through and out from receiver to terminal B from latter toiiange 36 to nose 34 of switch strip 23 and from latter to strip 19 toterminal A and out to line, from thenceit enters the other transmitterat A and passes through it and the receiver in the reverse direction tothe battery wire 50 and opposite p ole of battery. To send a signal thecircuit is from battery to terminal E from latter to key 19 when thelatter is pressed down from key to terminal A out to line and terminalAof the other instrument from latter by key 19 to switch strip 23 fromlatter to strip 32 as the receiver which is in the transmitter ispressing the switch 23 into contact with said strip out to terminal D bywire to bell and to return wire or earth 49.

1. In a telephone transmitter, a microphone formed of or containing aloose mass of separated carbonized bers, such as carbonized cottonfibers, substantially as described.

2. In a telephone transmitter, a microphone comprising hard carbonblocks, with cupshaped interior surfaces, between which is placed a massof loose carbonized fiber, substantially as described.

3. In a telephone transmitter a microphone formed of or containing acarbonzed fiber such as carbonized cotton ber with an admixture ofplumbago or other finely divided carbon substantially as described.

4. In a telephone receiver and in combination with the magnets coil anddiaphragm, a base plate, the case such as 43, ring such as 42, adaptedto maintain the coils and magnet at a determined distance from thediaphragm, the mouthpiece and clamping means, such as the ring 44, forsecuring the parts together substantially as described.

5. In combination, a receiver, a transmitter, a ringing key, a ring suchas 9 connected with same, holes in said ring, holes in the body of theinstrument, a switch board carrying a number of contact plates withholes therein, means for normally holding the ring so that the holes insame will be out of line with the others, a plug adapted to shift thering and make contact with the plates of the switch board and studscarried by the ring and by the switchboard adapted to be moved fromcontact with each other when the plug is iu substantially as described.

6. In a combined telephone transmitter receiver ringing key andswitchboard a pivoted block such as 13 a metallic strip carried by saidblock terminal blocks such as E F ring 9 adapted to rock the block 13 tocause the strip to make contact with one or other of the blocks E F,means for rocking the ring, a stud 12 carried by the ring, a contactplate 3 on theswitchboardstud 45 on said plate normally in contact withthe said stud 12 and means for breaking such contact substantially asdescribed.

7. The combination with the case or body 2, having a central opening, ofa plate secured to the case, a rear microphone block secured to theplate and extending through the opening in the case, a diaphragm mountedon the case and a front microphone block secured to the diaphragm,substantially as described.

8. The combination with a yoke as 37 having beveled sides of a receiverhaving a corresponding beveled mouth piece said receiver adapted toslide into the yoke and a switch adapted to be operated by the wedgingaction of the receiver substantially as described.

9. In combination a circular intercommunicating switchboard a circularsliding ring a rocking block operated by the same for connecting earthor battery to line and means for operating the sliding ringsubstantially as described.

10. In combination, the ring 9, strip 18 and key 19 connected theretoringing key 21`base or switchboard, stud 5 and `block 4 substantially asdescribed.

11. In combination, the key 19, switch 23 normally in contact therewith,stud 5 with which the key can make contact, strip 32 with which theswitch is adapted to make contact, nose 34 carried by the switch andyoke 37 with which the nose of the switch can make contact substantiallyas described.

12. The combination with a telephone apparatus of a rocking device awire to which normally all the instruments are connected TOO IIO

and a battery Wire,the rocking device acting In testimony whereof l havehereunto set to disconnect the apparatus desiring to call my hand in thepresence of two subscribing another station from that pole of thebattery Witnesses. to which it is normally connected and to con- GEORGELEE ANDERS. nect it tothe opposite pole so that the use of Witnesses:

a third Wire is dispensed with substantially as described.

PHILIP M. JUSTICE, ALLEN PARRY JONES.

